From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wright Subject: Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support Date: Thu, 15 Jul 2010 10:25:06 -0700 Message-ID: <20100715172506.GB14017@sequoia.sous-sol.org> References: <1279086307-9596-1-git-send-email-eduard.munteanu@linux360.ro> <4C3E2C2E.70507@codemonkey.ws> <20100714222401.GB21126@sequoia.sous-sol.org> <201007151128.27487.paul@codesourcery.com> <20100715165214.GV14017@sequoia.sous-sol.org> <4C3F3F0D.1000103@redhat.com> <20100715171710.GZ14017@sequoia.sous-sol.org> <4C3F43D7.1040301@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Chris Wright , Paul Brook , Anthony Liguori , Joerg Roedel , Eduard - Gabriel Munteanu , qemu-devel@nongnu.org, kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from sous-sol.org ([216.99.217.87]:34586 "EHLO sequoia.sous-sol.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933900Ab0GORZx (ORCPT ); Thu, 15 Jul 2010 13:25:53 -0400 Content-Disposition: inline In-Reply-To: <4C3F43D7.1040301@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: * Avi Kivity (avi@redhat.com) wrote: > On 07/15/2010 08:17 PM, Chris Wright wrote: > > > >>For emulated device, it seems like we can ignore ATS completely, no? > >Not if you want to emulate an ATS capable device ;) > > What I meant was that the whole request translation, invalidate, dma > using a translated address thing is invisible to software. We can > emulate an ATS capable device by going through the iommu every time. Well, I don't see any reason to completely ignore it. It'd be really useful for testing (I'd use it that way). Esp to verify the invalidation of the device IOTLBs. But I think it's not a difficult thing to emulate once we have a proper api encapsulating a device's dma request. thanks, -chris